Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2015

Fair Value Disclosures [Abstract]

Assets (Liabilities) Measured at Fair Value on a Recurring Basis

Assets (Liabilities) Measured at Fair Value on a Recurring Basis

(in millions)	June 30, 2015			Level 1		Level 2
Cash equivalents	$	1,705		$	1,705	$	—
Short-term investments
U.S. government and agency securities	138			77		61
Asset- and mortgage-backed securities	400			—		400
Corporate obligations	919			—		919
Other fixed income securities	37			—		37
Restricted cash equivalents and investments	47			47		—
Long-term investments	92			66		26
Hedge derivatives, net
Fuel hedge contracts	(758		)	8		(766		)
Interest rate contract	(8		)	—		(8		)
Foreign currency exchange contracts	89			—		89

(in millions)	December 31, 2014			Level 1			Level 2
Cash equivalents	$	1,612		$	1,612		$	—
Short-term investments
U.S. government and agency securities	59			—			59
Asset- and mortgage-backed securities	392			—			392
Corporate obligations	749			—			749
Other fixed income securities	17			—			17
Restricted cash equivalents and investments	37			37			—
Long-term investments	118			90			28
Hedge derivatives, net
Fuel hedge contracts	(1,848		)	(167		)	(1,681		)
Interest rate contract	(7		)	—			(7		)
Foreign currency exchange contracts	73			—			73